Plastic.

When Micro- waves first came out, you were warned not to put plastic in it just Iike metals! All milk and juice products came in cartons or glass, not plastic! Everyone cooked then meals not nuke them! This rabbit hole goes deep too! I remember my MIL getting hers and she stood in front of it to watch cook! She got 2nd degree burns on her face and had to see Dr.! People have been so dumbed down to iall this and led lights! Much to re-learn again! 🥰🙏🏼

I only buy grass-fed cows milk in cartons. Don't know how much better it is in a carton.

Milk is best in glass bottles. Only problem is the glass is rather heavy filled with milk. Most bottles are 1/2 gallon glass bottles. But it is such a pleasure to pour milk from a cold glass bottle. I will even transfer cartons of whole cream into glass bottles that I have at home.